Lots of companies, including for example telephone providers, internet providers, stores, public organisms, etc. dispose of telephonic hotlines. These hotlines enable the users to ask for support, information, and various services.
These hotlines are operated in dedicated places named call centres, can be a dedicated service of a company or a dedicated entity large enough to receive simultaneously thousands of calls (Some hotlines receive more than 120 millions calls a year). However, when a user calls, after having chosen the service he wants to reach, he often has to wait a few minutes: it may be up to an interlocutor could take his call, or up to his call could be transferred to another interlocutor if needed, or by the time the interlocutor works on his case, etc.
Indeed, most of call centres are PABX-based (Private Automatic Branch eXchange, i.e. a telephone switch which directs telephone calls). When a user dials the hotline telephone number, his call reaches the (or one of the) PABX of the call centre. At this point, if an interlocutor is available, the PABX directs the call towards this interlocutor, else the calling user is queued and put on hold as already explained.
During this waiting time, whose average length can be estimated to 3-4 minutes, music is generally played to entertain the user, this music being possibly punctuated by standard messages announcing for example that an interlocutor will respond soon. This is actually one or more recorded audio file: a PABX can store and play in a loop mp3 files, the users being connected to these audio files when put on standby. Alternatively, some PABX can listen to an external audio flow and play it, thus some hotlines continuously transmit the radio or a CD, or audio flows corresponding to advertisements about products of the company owning the hotline. A PABX may even be completed by a “Music On Hold” server, an equipment which delivers an audio flow to the PABX from various sources, including streaming via internet.
So millions of hours are wasted every year while waiting for a hotline to respond.
It could be interesting to play, during this waiting time, advertisements of the type of those which can be heard at radio. These radio advertisements are in the form of 15-30 seconds commercials, played at moments of the day chosen by the announcers.
However, as the waiting time of a telephonic hotline does not exceed a few minutes, the number of advertisements which can effectively be played to a user is relatively low. Moreover, as soon as the hotline is available, the on hold mode is stopped, and the currently played advertisement is cut: the advertisements shall not increase the waiting time.
To attract the announcers the five following objectives should be met:                the advertisements shall not be caught in the middle,        their frequency of apparition shall be controlled,        the set of advertisements shall regularly change        the advertisement shall touch an individual rather than a group (e.g. radio).        The announcer shall be able to interact with the calling user through promotional announces        
Yet, as already explained, a PABX is only able to continuously play an audio flux, and not to adapt it specifically to every user. So a PABX is not suitable as such for playing advertisements.
There is a need for a method enabling to play a sequence of advertisements as waiting message of a private automatic branch exchange. In particular, the invention aims at meeting the three objectives mentioned above.